A plasma display panel (hereinafter referred to as a PDP) has recently been drawing attention as a flat-type display device having a low profile, and a large screen. The dominating structure of PDPs is the AC type 3-electrode surface discharge PDP. The AC-type PDP contains a front substrate on which a plurality of pairs of scan electrodes and sustain electrodes is disposed in a row direction of the PDP, and a back substrate on which a plurality of address electrodes is disposed in a column direction. The front substrate and the back substrate are oppositely located so as to form discharge space therebetween. At each intersection of an address electrode and a pair of scan electrode and a sustain electrode, a discharge cell divided by barrier ribs is formed.
In the typical PDP operation, one field of image signals is divided into sub-fields each of which has a luminance weight—known as a sub-field method. In the method, gray levels of image signals are determined by a combination of the sub-fields. Each sub-field has an initializing period where the initial discharge is produced to generate predetermined wall charges; an address period where the address discharge is produced to select discharge cells to be turned on; and a sustain period where the sustain discharge is produced at the cell selected in the address period. Through light emission caused by the sustain discharge, images are shown on the screen.
Japanese Patent Unexamined Publication No. 2000-242224, for example, introduces a PDP driving method that provides improved contrast ratio by considerably decreasing the light emission in the initial discharge.
However, conventional manufacturing has sometimes produced a PDP with quality deficiencies, for example, the application of address pulse voltage to a cell fails to invite the address discharge, or in another case, the address discharge fails to trigger the successive sustain discharge. In the manufacturing processes, a PDP undergoes the light inspection prior to mounting driving circuits thereon; nevertheless, the conventional inspection method has sometimes failed to detect PDPs having the aforementioned problems.
The present invention addresses the pending problems. It is therefore the object to provide a method of detecting a PDP containing a defective discharge cell in which the sustain discharge does not occur in a proper sub-field.